Consider the following agricultural practices: 1. Contour bunding 2. Relay cropping 3. Zero tillage In the context of global climate change, which of the above helps/help in carbon sequestration/storage in the soil?

1. Carbon sequestration/storage in the soil refers to processes that remove carbon dioxide from the atmosphere and store it in the soil organic matter. 2. Statement 1: Contour bunding is primarily an agricultural practice focused on soil and water conservation, reducing erosion on sloping land. While preventing erosion helps retain existing soil carbon, it is not primarily a method for actively sequestering additional carbon. 3. Statement 2: Relay cropping is a form of multiple cropping that can increase overall biomass production and potentially add more organic matter to the soil compared to monocropping. However, its effect on carbon sequestration is variable and depends heavily on specific management practices (like residue management). It's not universally recognized as a primary carbon sequestration technique like no-tillage. 4. Statement 3: Zero tillage (or no-tillage) is an agricultural practice that avoids mechanical soil disturbance (ploughing). By leaving crop residues on the surface and minimizing soil disruption, it enhances the accumulation of soil organic matter and is widely recognized as a key practice for carbon sequestration/storage in agricultural soils, directly contributing to climate change mitigation. 5. Therefore, in the context of global climate change, Zero tillage (3) is the most direct and effective practice listed for carbon sequestration/storage in the soil.